During A330 training, various instructors will have many different types of equations and gateways used to confirm the descent profile and whether or not they are above or below glidepath.
The equations that I used now are
$$ \text{Wind} = \pm 1 \, \text{NM per} \; 5 \; \text{knots (head- or tailwind)} $$
$$ \text{Bleed off Speed} = 1 \, \text{NM per} \; 10 \; \text{knots or} \; 1.5 \, \text{NM per} \; 10 \; \text{knots during descent} $$
$$ \text{TOD} = \frac{\text{Altitude}}{1000} \times 4 $$
But I understand you would have to consider the aircraft weight, temperature, flap settings etc. but I'm not sure how to or even know where to start with that.
Would like to know your calculation or methodology! Any references would also be great!
